Will we lose all our beaches underwater as sea levels rise? Won’t it take years for new beaches to form?
In: Earth Science
In a lecture I attended by Neil deGrasse Tyson, he stated in a opinion/analogy that global warming really won’t be tackled until the beach resorts of the ultra-wealthy are endangered. Until then inaction would be paramount.
We will lose a lot of our beaches, despite what many people on here seem to think. If the coastline was a gently rising plane of substrate the sand could continue moving inland as the seas rises, preserving a beach at the edge of the water, but this simply isnt the case.
Large waves breaking hear shore in shallow water tend to remove sand from beaches and drag it off shore. Increasing storm frequency is leading to more of these large wave events that remove sand. This will shift the balance in many places from beach formation to beach erosion.
Sand gets deposited when breaking waves can slow as they run up a gentle slope, allowing the sand to settle out. In order to protect coastline development, we build sea walls and other barriers that prevent this, causing the waves that break into them to scour more sand and preventing sand from being deposited inland. On the west coast, many of the beaches are narrow and end at the base of cliffs. Sea level rise will reduce the width of the beach even further, making the cliffs into seawalls, regularly being hit by breaking waves, which will remove the rest of the beach. For example, I used to live near [this beach.](https://i1.wp.com/southocbeaches.com/wp-content/uploads/2016/12/strands-beach-march-8-2016-by-southocbeaches-com.jpg?resize=656%2C492&ssl=1) Then they built a housing development by terracing the cliff, put up a rock sea wall about 20 feet closer to the beach than the base of the cliff was, and within two years the sand along a large stretch that was closer to the high tide line was gone for much of the year, hence the walkway along the top of the wall.
Barrier islands and wetlands absorb storm energy and reduce flooding, while being a source of new sand. We are paving wetlands and barrier islands. In addition, when barrier island are topped by storm surge, they can rapidly be eroded away. Sea level rise couple with increasing storm frequency will make this more common.
Finally, increased inland flooding will pollute water and fill it with trash. Increased nutrient pollution tips the balance of the near shore scosystem towards blooms of toxic algae and increased jellyfish population. This will reduce the quality of beaches, even if the sand remains.
If you’re a young adult, by the time you retire your favorite beach will likely not be a place that you will find enjoyable to spend time at, if it exists at all.
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